1. Computer Science I
CSC 135

2. Computer Basics Hardware Software
CPU (central processing unit) – the “brains”
Memory – where information is stored
IO – input/output devices – for human interaction
Software
Computer Instructions – “programs”
OS (operating system)
Handles required “low level” tasks, provides a convenient interface for humans
Application programs
Human accessible - written for specific tasks

3. Modern computer, basic architecture
Inputs
Outputs
Central Processing Unit (CPU)
Control Unit (CU)
Arithmetic/Logic Unit (ALU)
Internal Memory
Registers
Main Memory*
Program
Data
Secondary Storage
Inputs
Keyboard, mouse, ...
Outputs
Monitor, printer, ...
Secondary Storage
Disk drive, USB stick, ...
(permanent/long term)
* shared program/data memory
(Von Neumann)

4. Modern Computer H
DRAM
Hard Drive
CPU

5. Binary Coding Binary is base 2 coding (vs. Decimal, which is base 10)
Counting in Binary 1 2 10 3 11 4
100 5
101 6
110 7
111 8
1000 9
1001
1010
Binary is base 2 coding (vs. Decimal, which is base 10)
Base 10 has 10 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Base 2 has only 2 “bits”: 0, 1
Bits is short for “binary digits”
Why?
It’s easier to make electronic circuits with 2 states rather than 10
Circuit only has to be “off” for zero or “on” for one – basically, a switch!
Works well with transistors (also with vacuum tubes or relays)

6. Memory Stores instructions and data
Address
Contents
(0)
(5)
(1)
(3)
(2)
(J)
(=)
(4)
(a)
(7)
(6)
(C)
(9)
(8)
(#)
Stores instructions and data
Every memory location has a numerical address
Contents are coded and stored in Binary format (ex: ascii)
Binary: “base 2” (next slide) …
Byte
Word
Bit

7. High Level Languages Binary coded instructions/programs
Called “machine code”
Low level (many steps to accomplish simple tasks)
Arcane – difficult to work with
Led to development of higher level languages
C, C++, FORTRAN, Basic, Java, …
Portable (same on any machine architecture)
User friendly, intuitive -> A=A+B
But, needs to be translated or “compiled” into machine code
Used extensively for application software development

8. Operating Systems
Designed for high level operation – two primary goals…
Handles general computer management tasks
Provides a friendly interface for human interaction
Built-in OS programs
Allow a user to perform useful tasks like:
Open, save, move, copy a file
Print information
OS Examples
Windows, Mac OS, Android, Unix/Linux, …

9. Operating Systems, Windows and Unix
Microsoft™ Windows
Standard OS for PC’s
GUI based, (originally built on DOS)
GUI: Graphical User Interface
Unix (used in this course)
Command based
Originally developed at Bell Labs™, written in C
Used extensively in science, engineering, networking
Linux is an open-source variant

10. Application programs
Special programs installed on the computer to accomplish specific tasks
Developed independently (not part of OS)
Examples:
Word processors, spreadsheets, presentations
This course will focus on developing programs using Unix and C++

11. Software development method
Specify the problem requirements
Analyze the problem
develop a strategy to address it
Design an algorithm (recipe) to solve the problem
Implement the algorithm
Write/develop the program!
Test and verify the completed program
Maintain and update the program

12. Steps in programming Write the program “compile” the program
Create a text file (Source File) in the programming language (emacs)
“compile” the program
Translate the source file into machine recognizable object code in an Object File
Using a “Compiler” (g++)
“link” the object code together with any other necessary Object Files
Other Object Files may come from other Source Files or generic libraries
Using a linker (g++)
Creates an Executable File (can be run, or executed, on the computer)
“load” (run) the Executable File
Uses a Loader to actually load and run the program

13. Program Development Write the program “compile” the program
Create Source File
“compile” the program
Generate an Object File
“link” Object Files, as needed
Create an Executable File
“load” (run) the Executable File

14. Professional Ethics Privacy and Misuse of Data Computer Hacking
Plagiarism and Software Piracy
Misuse of a Computer Resource
CSIT Academic Integrity Policy document
Located on the Computer Science and Information Technology Department home page at: